浊点萃取-流动注射电感耦合等离子体原子发射光谱法同时测定水中镉钴铜镍锌

本文提出了浊点萃取-流动注射电感耦合等离子体原子发射光谱（FI—ICP—AES）法同时测定水中镉、钴、铜、镍、锌的新方法。利用5-Br—PADAP将待测金属离子转化为水不溶性的螯合物，并萃取到表面活性剂Triton X-114的浓缩相，以乙醇-硝酸溶液稀释含富集离子的浓缩相，并以FI—ICP-AES法测定。考察了流动注射进样体积、积分时间、萃取体系介质酸度、螯合剂和表面活性剂用量等实验条件的影响。在折衷条件下，镉、钴、铜、镍和锌的浓缩倍率可达18、10、16、10和8，检出限分别为0．7μg／L、1．6μg／L、1．3μg／L、5．7μg／L、3．2μg／L。方法成功应用于自来水、河水和海水中痕量镉、钴、铜、镍和锌的分析。在0．02mg／L和0．10mg／L二个水平进行加入回收试验，回收率在80％与118％之间。     

Determination of Ultratrace Amounts of Copper(Ⅱ) in Water Samples by Electrothermal Atomic Absorption Spectrometry After Cloud Point Extraction

A novel approach was developed for the determination of ultratrace amounts of copper in water samples by using electrothermal atomic absorption spectrometry (ETAAS) after cloud point extraction (CPE). 1-( 2-Pyridylazo)-2-naphthol was used as the chelating reagent and Triton X-114 as the micellar-forming surfactant. CPE was conducted in a pH 8.0 medium at 40 ℃ for 10 min. After the separation of the phases by centrifugation, the surfactant-rich phase was diluted with 1 mL of a methanol solution of 0. 1 mol/L HNO3. Then 20 μL of the diluted surfactant-rich phase was injected into the graphite furnace for atomization in the absence of any matrix modifier. Various experimental conditions that affect the extraction and atomization processes were optimized. A detection limit of 5 ng/L was obtained after preconcentration. The linear dynamic range of the copper mass concentration was found to be 0-2.0ng/mL, and the relative standard deviation was found to be less than 3.1% for a sample containing 1.0 ng/mL Cu(Ⅱ). This developed method was successfully applied to the determination of ultratrace amounts of Cu in drinking water, tap water, and seawater samples.     

Determination of Ultratrace Amounts of Copper（ Ⅱ ） in Water Samples by Electrothermal Atomic Absorption Spectrometry After Cloud Point Extraction

IntroductionIn environment, copper is usually found in traceor ultratrace levels, and its detection requires sensitiveinstrumental measuring techniques such as electrother-mal atomic absorption spectrometry(ETAAS) and ICP-AES or ICP-MS. Frequently, a prec…     

Preconcentration and Determination of Tin in Water Samples by Using Cloud Point Extraction and Graphite Furnace Atomic Absorption Spectrometry

A method based on cloud point extraction and graphite furnace atomic absorption spectrometry (GFAAS) was developed for the analysis of trace tin in water samples. After cloud point extraction, the tin in the water samples was preconcentrated and successfully separated from most interferents. During the procedure, 8-hydroxyquinoline (8-HQ) was used as chelating reagent, and Triton X-114 was added as surfactant. The parameters affecting the sensitivity and the extraction efficiency, such as solution pH, concentration of 8-HQ and Triton X-114, equilibration temperature and centrifuge time, were evaluated and optimized. Under the optimum conditions, a preconcentration factor of 96.2 was obtained for a 20 mL water sample. The detection limit (LOD) was as low as 0.012 ng mL⁻¹, and the analytical curve was linear in the range of 0.05–2.0 ng mL⁻¹ with satisfactory precision (RSD <4.1%). The proposed method was successfully applied to the determination of trace tin in water samples with recoveries in the range of 85.0–112.0%.     

浊点萃取-石墨炉原子吸收光谱法测定环境样品中的痕量镉

研究了浊点萃取-石墨炉原子吸收光谱法(GFAAS)测定痕量镉的新方法,利用表面活性剂Triton X-100和络合剂1-(2-吡啶偶氮)-2-萘酚(PAN)对镉进行浊点萃取。详细探讨了影响浊点萃取及测定灵敏度的因素。优化条件为:0.25 mL 30%NaC l,pH 8.5,0.50 mL、4.0×10-4mol/L PAN,0.2 mL 1.0%TritonX-100。在最佳条件下,镉的富集倍率为50倍,检出限为5.9 ng/L,RSD为2.1%。该方法用于环境样中痕量镉的富集和测定,结果令人满意。     

Cloud point preconcentration and flame atomic absorption spectrometric determination of Cd and Pb in human hair

Cloud point methodology has been successfully used for the preconcentration of trace amounts of Cd and Pb as a prior step to their determination by flame atomic absorption spectrometry. O,O-Diethyldithiophosphate and Triton X-114 are used as hydrophobic ligand and non-ionic surfactant, respectively. After phase separation at 40 °C based on cloud point of the mixture, the surfactant-rich phase is diluted with methanol. The enriched analyte in the final solution is determined by flame atomic absorption spectrometry using conventional nebulization. After optimization of the complexation and extraction conditions, enhancement factors of 22 and 43 were obtained for Cd and Pb, respectively. Under the experimental conditions used, preconcentration of only 10 ml of sample in the presence of 0.05% (v/v) Triton X-114 permitted the detection of 0.62 μg l⁻¹ of Cd and 2.86 μg l⁻¹of Pb. The proposed method was applied to the determination of Cd and Pb in human hair samples.     

Cloud point extraction procedure for flame atomic absorption spectrometric determination of lead(II) in sediment and water samples

The conditions for cloud point extraction of lead(II) from aqueous solutions were investigated and optimized. The procedure is based on the separation of Pb(II) – brillant cresyl blue (BCB) complexes into the micellar media by adding the surfactant Triton X-114. After phase separation, the surfactant-rich phase was dissolved with 1 mol L⁻¹ HNO₃ in ethanol and diluted with 1 mol L⁻¹ HNO₃ solution before lead was determined by flame atomic absorption spectrometry. Optimization of the pH, ligand and surfactant quantities, incubation time, temperature, viscosity, sample volume, and interfering ions was performed. The effects of the matrix ions were also examined. The detection limits for three times the standard deviations of the blank for lead were 7.5 μg L⁻¹ for water samples and 0.33 μg g⁻¹ for sediment samples. The validity of cloud point extraction was checked by employing certified reference samples of Lake Sediment IAEA-SL-1 and Sewage Sludge BCR-CRM 144R. The procedure was applied to natural waters and sediment samples with satisfactory results (recoveries >95%, relative standard deviations <6.4%).     

浊点萃取-火焰原子吸收光谱法测定菠菜中镁、锌和铜

在pH 8.0缓冲溶液中,以8-羟基喹啉为螯合剂,镁、锌和铜均与8-羟基喹啉生成螯合物,加入Triton X-100表面活性剂用浊点萃取分离富集菠菜样品中镁、锌和铜。分取部分表面活性剂相用乙醇定容至25mL,所得溶液直接用火焰原子吸收光谱法进行测定。对影响浊点萃取的因素和共存离子的干扰等进行了试验并予以优化。镁、锌和铜的检出限(3s/k)依次为0.057,0.064,0.032mg.L-1。应用此法测定了大叶菠菜和小叶菠菜中3种元素的含量,在两种样品中用标准加入法进行方法的回收试验,测得镁的回收率在93.3%～100.5%之间;锌的回收率在91.7%～97.9%之间;铜的回收率在94.0%～107.1%之间。     

Simultaneous Solid Phase Chelate Extraction for Ultratrace Determination of Copper,Nickel, and Zinc by Microsample Injection System Coupled Flame Atomic Absorption Spectrometry

A simple and accurate solid phase extraction method was developed for the determination of Cu(II), Ni(II), and Zn(II) at trace levels by microsample injection system coupled flame atomic absorption spectrometry. The proposed method is based on the retention of complexes of metal ions with 4-(2-pyridylazo) resorcinol on Amberlite XAD-7 resin and elution with acetone. The possible parameters influencing the preconcentration were optimized. The interferences of coexisting ions were studied. Under the optimal conditions, the detection limits of Cu(II), Ni(II), and Zn(II) were 0.058, 0.013, and 0.027 µg L^?1, respectively. The applicability and the accuracy of the proposed method were validated by analysis of BCR 715 wastewater as a certified reference material and spiked real samples. Recoveries in the range of 94–105% were obtained with relative errors less than 7.5% and relative standard deviations less than 3.2%.     

Combination of cloud point extraction and flame atomic absorption spectrometry for preconcentration and determination of trace iron in environmental and biological samples

In the presented work, the conditions for cloud point extraction of iron from aqueous solutions using 7-iodo-8-hydroxyquinolin-5-sulphonic acid (Ferron) was investigated and optimized. The procedure is based on the separation of its ferron complex into the micellar media by adding the surfactant Triton X-114. After phase separation, the surfactant-rich phase was dissolved with 1.0 M HNO3 in methanol. Iron was determined by flame atomic absorption spectrometry. Optimization of the pH, ligand and surfactant quantities, incubation time, temperature, viscosity, sample volume, and interfering ions were investigated. The effects of the matrix ions were also examined. The detection limits for three times the standard deviations of the blank for iron was 0.4 ng m L-1, enrichment factor of 19.6 and preconcentration factor of 30 could be achieved. The validity of cloud point extraction was checked by employing real samples including soil, blood, spinach, milk, meat, liver and orange juice samples using the standard addition method, which gave satisfactory results.In the presented work, the conditions for cloud point extraction of iron from aqueous solutions using 7-iodo-8-hydroxyquinolin-5-sulphonic acid (Ferron) was investigated and optimized. The procedure is based on the separation of its ferron complex into the micellar media by adding the surfactant Triton X-114. After phase separation, the surfactant-rich phase was dissolved with 1.0 M HNO₃ in methanol. Iron was determined by flame atomic absorption spectrometry. Optimization of the pH, ligand and surfactant quantities, incubation time, temperature, viscosity, sample volume, and interfering ions were investigated. The effects of the matrix ions were also examined. The detection limits for three times the standard deviations of the blank for iron was 0.4 ng m L⁻¹, enrichment factor of 19.6 and preconcentration factor of 30 could be achieved. The validity of cloud point extraction was checked by employing real samples including soil, blood, spinach, milk, meat, liver and orange juice samples using the standard addition method, which gave satisfactory results.      

Cloud Point Preconcentration and Flame Atomic Absorption Spectrometric Determination of Cobalt and Nickel in Water Samples

 Cloud point methodology was successfully used to preconcentrate trace amounts of Co and Ni as a prior step to their determination by flame atomic absorption spectrometry. 1-Nitroso-2-naphthol and polyethylene glycol-p-nonylphenylether (PONPE 7.5) are used as hydrophobic ligand and nonionic surfactant, respectively. Optimization was performed of the variables effecting complexation and phase separation. Additionally, the influence of viscosity on the analytical signal was investigated. Under the experimental conditions used, preconcentration of only 10 mL of sample in the presence of 0.075% (v/v) PONPE 7.5 permitted the detection of 1.09 μg L⁻¹ of Ni and 1.22 μg L⁻¹ of Co with enhancement factors of 29 and 27 for Ni and Co, respectively. The relative standard deviations (n=5) at concentrations of 80 and 50 μg L⁻¹ for Co and Ni were 2.53 and 2.89%, respectively. Good recoveries in the range of 96–105% were obtained for spiked samples. The effect of different interferent species was studied. The proposed method was applied to the determination of Ni and Co in different water samples. Correspondence: Department of Analytical Chemistry, Faculty of Chemistry, Tabriz University, Tabriz, Iran. e-mail: manzoori@tabrizu.ac.ir Received September 1, 2002; accepted November 8, 2002     

Application of Graphene as a Sorbent for Simultaneous Preconcentration and Determination of Trace Amounts of Cobalt and Nickel in Environmental Water and Vegetable Samples

A new method using a column packed with graphene as adsorbent was developed for the preconcentration of trace amounts of cobalt (Co) and nickel (Ni) prior to their determinations by flame atomic absorption spectrometry. Several factors influencing the extraction efficiency of Co and Ni and their subsequent determinations, such as pH, amounts of the chelating agent, flow rates of sample and eluent solution, eluent type and its volume, breakthrough volume, and adsorption capacity were established. Under the optimum conditions, the calibration graphs were linear in the range of 4.0‐200.0 μg L^?1 and 5.0‐200.0 μg L^?1 with detection limits of 0.36 μg L^?1 and 0.51 μg L^?1 for Co and Ni, respectively. Good relative standard deviations for ten determinations of 100.0 μg L^?1 of Co and Ni were 3.2 and 3.6%, respectively. The results for determination of Co and Ni in tap water, river water, sea water, vegetable and spiked samples have demonstrated the accuracy and applicability of the proposed method. To validate the proposed method, three certified reference materials of environment water (GSBZ 50030‐94 and GSB 07‐1186‐2000) and tomato leaf (GSBZ 51001‐94) were analyzed, and the determined values were in good agreement with the certified values.     

浊点萃取分光光度法测定水样中的痕量锌(Ⅱ)

为建立浊点萃取预富集测定水样中痕量锌的新方法,在表面活性剂TritonX-114存在下,利用5-Br-PADAP与锌(Ⅱ)产生显色反应的性能,采用分光光度法测定了水样中的痕量锌。结果表明,在pH8.5的NH3-NH4Cl缓冲体系中,锌(Ⅱ)与5-Br-PADAP形成紫红配合物,其最大吸收波长为λ=555 nm,摩尔吸光系数为ε=1.284×105L.mol-1.cm-1,检测限为0.003 7μg.mL-1.锌含量在0~1.2μg.mL-1范围内服从比尔定律。该法有较好的选择性,具有低毒、高效、安全、简便等特点,直接用于水样中痕量锌的测定,结果满意,重复6次测定相对标准偏差为2.18%。     

A Pre-Concentration Procedure Using Cloud Point Extraction for the Determination of Manganese in Saline Effluents of a Petroleum Refinery by Flame Atomic Absorption Spectrometry

This paper describes the development of a cloud point extraction procedure for the determination of manganese in saline effluents by flame atomic absorption spectrometry (FAAS). The optimization step was performed using the Doehlert matrix involving the following variables: buffer concentration, pH and centrifugation time. The validation process was assessed as: parameters of the analytical curve, precision, effect of other ions in the proposed procedure, robustness test and accuracy. The proposed procedure allows the determination of manganese with a detection limit (3δ/S) of 0.60 μg L⁻¹, and a precision expressed as relative standard deviation (RSD) of 2.2 (n = 8) and 1.5% (n = 8) for a manganese concentration of 1 and 5 μg L⁻¹, respectively. The pre-concentration factor obtained was 84. The recovery achieved for the determination of manganese in the presence of several other metal ions demonstrated that this procedure could be satisfactorily applied to the analysis of environmental samples. The accuracy was confirmed by the analysis of CRM trace elements in water (NIST 1643d). This procedure was applied to the determination of manganese in saline effluents of a petroleum refinery. For three analyzed samples the manganese content varied between 44.9 and 67.9 μg L⁻¹.     

Development of an Efficient Procedure for Determination of Copper,Zinc and Iron after Solid Phase Extraction on 3‐(1‐(1‐H‐Indol‐3‐yl)‐3‐Phenylallyl)‐1H‐Indole Loaded on Duolite XAD 761

A method for the simultaneous preconcentration of Cu²⁺,Zn²⁺ and Fe³⁺ ions, in some food samples has been reported. The method is based on the adsorption of 3‐(1‐(1‐H‐indol‐3‐yl)‐3‐phenylallyl)‐1H‐indole (IPAI) loaded on Duolite XAD 761. The metal ions adsorbed on the modified solid phase resin are eluted using 6 mL of 4 mol L^?1 nitric acid. The influences of the analytical parameters including pH and amount of ligand and solid phase and type and amount of surfactant and sample volume on the metal ions recoveries were investigated. The effects of matrix ions on the retentions of the analytes were also examined. The recoveries of analytes were generally higher than 95% with a RSD lower than 5%. The method has been successfully applied for these metals content evaluation in some real samples.     

Selective determination of total vanadium in water samples by cloud point extraction of its ternary complex

A highly sensitive micelle-mediated extraction methodology for the preconcentration of trace levels of vanadium as a prior step to its determination by flame atomic absorption spectrometry (FAAS) has been developed. Vanadium was complexed with 1-(2-pyridylazo)-2-naphthol (PAN) and hydrogen peroxide in acidic medium (0.2 mol L⁻¹ phosphoric acid) using Triton X-100 as surfactant and quantitatively extracted into a small volume of the surfactant-rich phase after centrifugation. The color reaction of vanadium ions with hydrogen peroxide and PAN in phosphoric acid medium is highly selective. The chemical variables affecting cloud point extraction (CPE) were evaluated and optimized. The R.S.D. for 5 replicate determinations at the 20 μg L⁻¹ V level was 3.6%. The calibration graph using the preconcentration system for vanadium was linear with a correlation coefficient of 0.99 at levels near the detection limits up to at least 0.6 μg L⁻¹. The method has good sensitivity and selectivity and was applied to the determination of trace amounts of vanadium in water samples with satisfactory result. The proposed method is a rare application of CPE-atomic spectrometry to vanadium assay, and is superior to most other similar methods, because its useful pH range is in the moderately acidic range achieved with phosphoric acid. At this pH, many potential interferents are not chelated with PAN, and iron(III) as the major interferent is bound in a stable phosphate complex.     

Speciation Determination of Chromium(VI) and Chromium(III) in Soil Samples after Cloud Point Extraction

Abstract

To measure the different activity of chromium(VI) and chromium(III) in soil samples, chromium(VI) and total chromium (CrVI + CrIII) was extracted by KCl extracting agent and alkali fusion, respectively. Cloud point extraction (CPE) for speciation determination of chromium with double-slotted quartz tube atom trap–flame atomic absorption spectrometry (STAT-FAAS) was developed. Preconcentration of chromium(VI) and total chromium in different pH solutions was achieved by CPE, with ammonium pyrrolidine dithiocarbamate (APDC) as the chelating agent and Triton X-114 as the cloud point extractant. The conditions of CPE and determination were studied. Under the optimal conditions, the enrichment factor was 50 for chromium from the initial 100-mL sample solution to the final 2-mL determined solution. Compared to the FAAS method, the sensitivity was improved seven-fold for chromium by the STAT-FAAS method. The limit of detection was 0.082 µg/L for chromium.     

微柱高效液相色谱法测定环境样品中的铁、钴、镍、铜、锌、锰

研究了用 2-(2-喹啉偶氮 )-间苯二酚 (QAR)为柱前衍生试剂 ,以WatersXterraTM RP18(1 .0×5 0mm ,2. 5 μm)微柱为固定相 ,60 %的甲醇 (内含 0 . 5 %的醋酸 )为流动相 ,高效液相色谱分离、二极管矩阵检测器测定铁、钴、镍、铜、锌和锰的方法。根据信噪比 (S N =3 )得各金属离子的检测限分别为 :铁3 μg L、钴 4μg L、镍 2 μg L、铜 4μg L、锌 5 μg L、锰 8μg L ,方法用于环境样品中痕量铁、钴、镍、铜、锌、锰的测定 ,相对标准偏差在 1 . 6%～ 3 . 5 %之间 ,标准回收率为 93 %～ 1 0 7%。     

空气 - 乙炔火焰原子吸收法连续测定铜粉中微量Fe、Pb、Sb、Zn和Ni

用HNO3-HCl溶解试样,在几个相同量的试液中,分别加入质量浓度依次递增的5种元素的标准溶液,用火焰原子吸收法连续测定了Fe、Pb、Sb、Zn和Ni的含量,建立了优化的仪器测定条件,并对可能存在的元素进行了干扰试验。结果表明,Fe、Pb、Sb等5种元素的回收率为98.0%～102.3%,相对标准偏差为1.4%～2.5%。